Kurt then made some comment about the inadequacy of a materialistic worldview, and how, without God as the basis of morality, the whole planet would degenerate into what we saw at Virginia Tech. I replied that the prevention of suffering seemed like a pretty good basis for morality to me.

I'm an atheist and certainly in agreement with Scott Aaronson that God is not a valid basis for morality. But I don't agree that prevention of suffering is a good replacement. Here is my reason:

What counts as suffering? Is it a matter of subjectively feeling bad? If so, a rapist would be in the right if restraint would cause him to feel worse than his victim will feel.

That's perverse. To avoid that category of faults we'll have to consider only impartial ways of evaluating suffering. That way if a person gets really upset about not having his way that does not automatically make him morally right. There are many possible ways to measure suffering objectively, but they all share a common flaw.

To explain the flaw, I will establish two facts. First, because our way of measuring suffering is part of the explanation of how the basis of morality works, it is prior to morality. It cannot use morality as part of it's measurement: that would be circular. Second, in order to work, our way of measuring suffering must take into account people's preferences. Does Sue want to have sex with Bob, or not? Does Joe like apples, or not? If it ignores preferences like these, it will incorrectly judge the suffering involved in sexual encounters and apple shortages.

The flaw comes from considering preferences while simultaneously thinking prior to morality. There is no valid way to judge the morality of the preferences being considered; there's no way to judge if they are wrong to hold, or should be changed. The result must be to make incorrect judgments about situations in which the right thing is for someone to change his preference.

We might try to invent ways of considering whether preferences are right to hold, and when they should be changed. But what we'd be doing, in effect, is reinventing morality. (Morality deals with how to live including which preferences are best to have.) If any morality is part of a proposed basis for all of morality, then that basis is circular.

My take on morality is that there is a careful way of thinking about morality such that the basis is virtually irrelevant: the vast majority of morality remains the same regardless of the chosen basis. You can even use something very silly like maximizing the number of live squirrels. I believe the parts of morality that are the same for a wide variety of bases are what we really know about morality. If that sounds interesting, read my explanatory dialog.